# GOL-019: Safe Passage

Isolated cells follow their compass and cannot die. Other cells seek adjacent survival opportunities; competing claims cancel movement.

[Open simulation](https://100gol.com/experiments/019) · [Directory](https://100gol.com/experiments)

## What to explore

Reveal how local survival seeking reshapes Life when every organism has the same
opportunity and nobody wins a collision arbitrarily. Movement, failed claims,
and the difference between a site's next occupancy and its occupant's fate must
be explainable. The intended question is whether migration and contention sustain themselves;
verification found both settling and sustained regimes under composed masks.

## Rules, update order and replay

Square Moore lattice, 80, 120 or 160 square; toroidal by default, optional bounded
edges. Codes 0–7 proceed clockwise from NW: NW, N, NE, E, SE, S, SW, W.
This puts east at three in this experiment; Compass Rose's north-zero labels
are deliberately not imported. Each living organism owns heading and permanent
rotation sense. Positions own independent seeded birth random streams. Complete
state includes binary occupancy, headings, senses, private elapsed-turn counters, birth streams, clockwise
assignment percentage, generation and previous-Step events/proposals/claims.

One synchronous Step freezes the board and all Moore counts. Each living cell
considers only frozen-empty immediate neighbors. The candidate count is that
position's frozen count minus one, removing the source organism. It qualifies
if the survival mask includes this count. The nearest circular angular distance
to the current heading wins; an equal distance favors the organism's rotation
sense. The current heading is used first; a due compass turn happens after
acting. The Compass turn interval is 0–15 Steps, default one. At N > 0, each
organism turns one slot after its own Nth, 2Nth, etc. completed Step. Zero holds
its heading indefinitely without disabling movement. Blocked Steps count too.
Movers carry their elapsed counter; newborns begin at zero. This counts engine
Steps rather than browser redraws, including during Fast playback.
All living cells seek movement, including cells that could survive in place.

The isolated-cell rule has precedence over both masks: a living organism with
zero neighbors in the frozen starting field cannot die this Step and proposes
only its current compass direction, without testing destination survival. If
that direction leaves a bounded field, it stays alive without selecting an
alternative. A contested isolated move also stays alive in place. Protection
lasts for this Step even if the destination puts it beside another organism;
with one or more neighbors on a later Step, the ordinary rules apply again.

Each organism proposes once. Exactly one claim accepts a move and guarantees
that organism's survival this Step. Multiple claims reject every contender;
there is no retry, swap, chain into a vacancy or global priority. Nonmovers
survive unconditionally at zero neighbors; otherwise they apply the survival
mask at their original frozen count. Frozen-dead unclaimed
positions apply the birth mask at their frozen count; a successful arrival
supersedes a birth, while a contested destination may still have an ordinary
birth. A departed source stays empty until at least the following Step. All
results commit together. Arrivals do not get a second Life test on a changed
board. Forecasting a candidate reads at most the source's radius-two field.

Movers carry their compass and elapsed counter. Stationary survivors tick too. Death
removes organism compass state; a later birth draws a fresh heading and sense
from that position's private stream. Newborns first act next Step. Randomness
assigns compasses only and never breaks movement conflicts. Reset recreates the
selected initial board and all hidden state from independent world and compass
seeds. Clear recreates an empty field. Painting a new organism consumes a local
birth assignment; erasing removes its compass. Painting clears transient evidence.
Replay requires all state arrays plus dimensions, topology and configuration.

## Reading the simulation

Canvas 2D: lime survivors, cream newborns, cyan arrivals, coral surviving blocked
contenders; dead cells remain background. Inspector outlines eight candidates,
marks the chosen destination, and reports frozen/source-adjusted counts,
angular ranking, claims, current/advanced compass, source fate, next site
occupancy and last-Step evidence. An explicit Isolation rule row and organism
fate name protected movement, protected conflict, or protected boundary rest.
The Turn clock row exposes elapsed Steps, remaining Steps, and Off; the heading
pair reports whether the next Step holds or turns. Only the compass direction qualifies for an isolated organism; other directions
are labeled Not heading and the destination counts are diagnostic. Written labels retain all causality when Color
is simplified. Arrow keys select, Enter paints outside inspection, P toggles
playback and S steps. Inspect pauses painting. The mobile randomizer follows the
legend and instructions and uses the same reset/play handler as the rail.

## Reproduce a starting configuration

[Download example JSON](https://100gol.com/api/experiments/019/configuration). Import it using Share & reproduce in the simulation controls. It starts paused at Step zero. Files contain rules and initial conditions, not evolved boards or manual edits. See [format, limitations and automated access](https://100gol.com/agents).